According to some nonlimiting examples, the optical system can be incorporated into an image acquisition system, which may be a disposable camera, a digital camera, a reflex camera (digital or non-digital), a scanner, a fax machine, an endoscope, a motion picture camera, a video camera, a surveillance camera, a toy, a camcorder or camera incorporated into or connected to a telephone, personal digital assistant or computer, a thermal camera, un ultrasound device, an MRI (magnetic resonance) imaging device, or an X-ray radiography device.
An image acquisition system generally comprises, in addition to an optical system whose role is to focus light, a sensor. Such a sensor comprises mechanical, chemical or electronic means for capturing and/or recording images.
The sensor is, for example, a system of photosensitive cells that transforms the quantity of light received into numerical values, and that assigns to each pixel the value or values that correspond to it. The unprocessed image acquired directly by the sensor is traditionally called the RAW image. The number of numerical values ultimately assigned to each pixel depends on the image capturing system.